With the introduction of portable digital media players, the compact disk for music storage, and audio delivery over the Internet, it is now common to store, buy and distribute music and other audio content in digital audio formats. The digital audio formats empower people to enjoy having hundreds or thousands of music songs available on their personal computers (PCs) or portable media players. This facilitates listening to any desired music in a wide variety of settings.
People like listening to music in dance and workout situations. Custom playlists of songs from different artists, albums and genres are commonly used. Portable players have long been used during individual workout situations. Now that portable media players have capacity to store larger music collections and custom playlists, portable players also are used by instructors in combination with a speaker or amplification system in group situations, such as for workout and dance classes.
In dance and workout situations, it can be desirable to have one song transition smoothly into the next (e.g., without a perceptually significant 0th or 1st order beat discontinuity). This permits the activity (dance or workout) to continue un-interrupted for longer than the duration of a single song, while allowing a variety in music selection over the course of the activity (such as to provide a mood change or other desired effect). In many dance and workout situations with a live DJ, listeners have now come to expect transitions with beat continuity between songs.
Various techniques are known and in use for seamlessly transitioning between songs. For example, disk jockeys (DJs) can use manual or automated techniques to queue and transition between songs at a dance, or in broadcasting. Software applications also are available on a personal computer that provide various audio recording, mixing, editing and mastering features, and can be used to achieve transitions between music tracks with beat continuity. However, these techniques involve considerable digital analysis and manipulation of the sound recordings. On the other hand, portable digital media players generally have limited computational power. Currently available portable media players with limited computational capacity have lacked the capability to perform song transitions without beat discontinuity.